Influence of Surface Pretreatment on Carbon Coating of Cutting Tools Using PVD

Abstract

Alumina (Al2O3) cutting tools have been coated with carbon coating using physical vapor deposition (PVD) to improve its wear resistance. The cutting tools were subjected to surface pretreatments namely blasting and acid etching to improve the coating adhesion onto the substrates. The effects of pretreatments on the cutting tools topography prior to deposition were investigated using atomic force microscopy (AFM) while the surface morphology was investigated using scanning electron microscopy (SEM). The rake angle of the coated cutting tool and surface roughness of the cutting edge were investigated using infinite focus microscope. The adhesion strength of the carbon coating was investigated using microscratch. This study shows that although the coating were deposited evenly on all samples, the cutting tool that was blasted prior to deposition has better adhesion strength when compared to acid etching and no-pretreatment.